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Merge tag 'fuse-update-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
- Fix lots of bugs, most from the late 6.x era, but some going back
to 2.6.x
- Add subsystems (io-uring, passthrough) and respective maintainers
(Bernd, Joanne and Amir)
- Separate transport and fs layers (Miklos)
- Don't block on cat /dev/fuse (Joanne)
- Perform some refactoring in fuse-uring (Joanne)
- Don't use bounce-buffer for READDIR reply in virtio-fs (Matthew Ochs)
- Clean up documentation (Randy)
- Improve tracing (Amir)
- Extend page cache invalidation after DIO (Cheng Ding)
- Invalidate readdir cache on epoch change (Jun Wu)
- Misc cleanups
* tag 'fuse-update-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (81 commits)
fuse-uring: clear ent->fuse_req in commit_fetch error path
fuse-uring: use named constants for io-uring iovec indices
fuse-uring: refactor setting up copy state for payload copying
fuse-uring: use enum types for header copying
fuse-uring: refactor io-uring header copying from ring
fuse-uring: refactor io-uring header copying to ring
fuse-uring: separate next request fetching from sending logic
fuse: invalidate readdir cache on epoch bump
virtio-fs: avoid double-free on failed queue setup
fuse: invalidate page cache after DIO and async DIO writes
fuse: set ff->flock only on success
fuse: clean up interrupt reading
fuse: remove stray newline in fuse_dev_do_read()
fuse: use READ_ONCE in fuse_chan_num_background()
fuse: dax: Move long delayed work on system_dfl_long_wq
fuse: add fuse_request_sent tracepoint
fuse: Add SPDX ID lines to some files
fuse: use QSTR() instead of QSTR_INIT() in fuse_get_dentry
fuse: convert page array allocation to kcalloc()
fuse: use current creds for backing files
...
FUSE_NOTIFY_INC_EPOCH invalidates dentries, but does not invalidate cached
readdir results. A process with cwd inside a FUSE mount can therefore
observe stale readdir(".") output after an epoch bump.
Fix this by recording epoch in the readdir cache and checking it on reuse.
Minimal reproducer:
- mount a tiny FUSE fs with an empty root directory
- on opendir, enable fi->cache_readdir and fi->keep_cache
- chdir into the mount and call readdir(".") to populate readdir cache
- make the FUSE server report one file in the root directory
- send only FUSE_NOTIFY_INC_EPOCH
- call readdir(".") again; before this change it stays stale, after this
change it sees the new file
Fixes: 2396356a94 ("fuse: add more control over cache invalidation behaviour")
Signed-off-by: Jun Wu <quark@meta.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
FUSE_NOTIFY_PRUNE validates the nodeid payload length with:
size - sizeof(outarg) != outarg.count * sizeof(u64)
On 32-bit kernels, size_t is also 32 bits, so the daemon-controlled
count multiplication can wrap. A prune notification with count
0x20000000 and no nodeid payload passes the check, enters the copy
loop, and asks the device copy path to read nodeids that are not
present in the userspace write buffer. In QEMU this reaches the
fuse_copy_fill() BUG_ON(!err) path.
Validate the payload length with array_size() instead. That accepts
exactly the same valid messages, but avoids wrapping arithmetic before
the copy loop consumes the count.
Assisted-by: Codex:gpt-5.5-cyber-preview
Fixes: 3f29d59e92 ("fuse: add prune notification")
Cc: stable@vger.kernel.org
Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
